Preselection diaphragm structure for photographic cameras



' Filed sept. 27, 195e Jan. l0, 1961 K. GEBELE 2,967,472

PRESELECTION DIAPHRAGM STRUCTURE FOR PHOTOGRAFHIC CAMERAS 2 Sheets-Sheet1 UEM Jan. l0, 1961 K. GEBELE 2,967,472

PRESELECTION DIAPHRAGM STRUCTURE FOR PHOTOGRAPHIC CAMERAS Filed Sept.27, 1956 2 Sheets-Sheet 2 M 38 gm PRESELECTION DIAPHRAGM STRUCTURE FORPHOTOGRAPHIC CAMERAS Kurt Gehele, Munich, Germany, assignor, by mesneasslgnments, to Compur-Werk Friedrich Deckel OHG., Munich, Germany, afirm f Germany Filed Sept. 27, 1956, Ser. No. 612,465

Claims priority, application Germany Sept. 29, 1955 2 Claims. (Cl.95--64) This invention relates to a preselection diaphragm forphotographic cameras of the type in which the diaphragm is in aninterchangeable lens unit detachable from and replaceable on a shutterunit.

In certain types of cameras, particularly single lens reliex cameras, itis desirable to have the shutter blades and the diaphragm leaves fullyopen to their respective maximum apertures, when focusing the camera,access of light to the lm being prevented at this time by suitable meanssuch as the reflex mirror. When focusing is completed and the picture isto be taken, the shutter blades are closed prior to moving the mirror topicture-taking position, and it is desirable to cfose down the diaphragmleaves to a previously determined or previously selected aperture,before the shutter blades are again opened to make the actual exposure.Hence a diaphragm of this kind may be referred to as a presele1tiondiaphragm, meaning that after the diaphragm leaves have been opened tomaximum aperture for focusing, they are closed down again to thepreviously selected aperture, before the picture is taken, withoutfurther special attention on the part of the operator.

An object of the invention is the provision of a generally improved andmore satisfactory structure of this kind.

Another object is the provision of di^phragm mechanism mounted in aninterchangeable unit and coupled by simple means to a shutter unit onwhich the interchangeable unit is mounted, the coup ing means being soconstructed that the diaphragm is moved to its preselected positionbefore the shutter blades are opened to make the exposure.

Stil] another object is the provision of coupling means between theinterchangeable unit andthe shutter unit, so designed that the couplingmeans becomes fully effective for its intended purpose, no matter inwhat position or condition the diaphragm may happen to be at the timethat the interchangeable unit carrying the diaphragm is mounted on theshutter unit.

These and other desirable objects may be attained in the mannerdisclosed as an illustrative embodiment of the invention in thefollowing description and in the accompanying drawings forming a parthereof, in which:

Fig. 1 is a plan of a camera equipped with a shutter unit and aninterchangeable 1ens and diaphragm unit, the latter unit being shownslightly separated from the shutter unit in a position assumed whenbeing placed on or taken off of the shutter unit.

Fig. 2 is a fragmentary radial section through a portion of the camerabody, the shutter unit, and the interchangeable lens and diaphragm unit,the section being taken along the optical axis;

Fig. 3 is a fragmentary section through the same, taken perpendicular tothe optical axis approximately on the line 3--3 of Fig. 2;

F ig. 4 is a fragmentary transverse section approximately on the line4--4 of Fig. 2;

Fig. 5 is a fragmentary radial section similar to a pornited StatesPatent 2,967,472 vPatented Jan. 10, 1961 fice tion of Fig. 2 but takenon a diEerent radius, illustrating additional details; and

Fig. 6 is a View similar to a fragment of Fig. 2, illustrating aslightly modified construction.

The same reference numerals throughout the several views indicate thesame parts.

Referring first to Fig. l, there is shown a photographic camera having amain body 1 of suitable known construction, including a iilm winding oradvancing knob 2, a film rewinding knob 3, and a release plunger ortrigger 4.

Referring now to Figs. 2 and 3 in addition to Fig. l, the front wall 10of the camera has attached to it the usual casing or housing 12 of anobjective shutter, of genera'ly annular cylindrical shape, the annularspace within the housing containing the usual base plate or mechanismmounting plate 14 of annular form, from the inner circumference of whichthe front threaded tube 18 extends forwardly. The shutter speed settingring 16 is rotatable on the outside of the tube 1S near the forward endthereof, so as to turn about the optical axis of the shutter as acenter, and the turning of this speed setting ring 16 serves to adjustthe time of exposure in the usual known manner, controlling the speed atwhich the shutter operating mechanism within the annular part of theshutter housing opens and closes the usual shutter blades mounted in thespace just behind the base plate 14. The details of construction of theshutter mechanism, except for the points specically mentioned below, arenot important for purposes of the present invention and may be of anysuitah'e known form.

Fastened to the front of the tube 18 is a stationary bayonet connectionring 2li which serves also as a cover for the front end of the shutter,overlying the shutter speed adjusting ring 16. The ring 20 has at itsfront end the usual bayonet connection lugs or flanges which mate withbayonet connection lugs or lianges near the rear end of theinterchangeable lens and diaphragm unit, which unit is made up of thetwo main parts 22 and 24 fastened t-o each other and serving to carrythe usual lens elements or components 25, one or both of which may bemounted for axial movement for focusing purposes. ln the particularconstruction here shown, the forward one of the lenses 25 is mounted ina screw threaded sleeve which, upon being rotated by the milled ring atthe front of the unit, travels axially forwardly or rearwardly forfocusing purposes.

ln the space 26 between the two housing parts 22 and 24 of theinterchangeable unit, there is mounted a diaphragm or stop comprisingthe usual iris diaphragm leaves or bades 2S, adjusted by an adjustingring 30 rotatable about the optical axis as a center. The ring has anoutwardly extending arm 32 passing through a slot 34 and divided intotwo parts, one of which extends axially rearwardly a short distance asseen in Fig. 5, the other of which extends forwardly and thence radiallyoutwardly through an arcuate slot to a linger piece by which it can beactuated to adjust the diaphragm.

Movement of the ring 3i) and arms 32 in a clockwise direction, whenviewed as in Fig. 3, serves to open the diaphragm leaves 28 to a largeraperture, while counterclockwise rotation closes down the aperture ofthe diaphragm. A spring 36 extending circumferentially and connected atone end to the arm 32 and at the other end to a fixed pin in thehousing, tends constantly to turn the ring 30 in a counterclockwisedirection and thus to close down the diaphragm aperture, to an extentpermitted by engagement of the arm 32 with a radially extending abutmentsurface 40 on the external diaphragm setting ring 33 which is rotatablecircumferentially on the interchangeable lens unit body 22, 24. Theperiphery of the ring 38 carries the usual diaphragm aperture scalewhich is read in conjunction with the stationary pointer 42.

In addition to its rotary movement (about the optical axis as a center)for adjusting the preselected aperture of the diaphragm, the settingring 38 is also displaceable in an axial direction to a limited extent,and is constantly urged rearwardly by the action of springs 44, so as tokeep a coupling tooth 46 on the ring 38 in engagement with one oranother of the coupling notches 48 formed at the front edge of theexternally accessible speed setting ring 50 which is coupled to theinternal shutter speed setting ring i6 to turn therewith, by means of adriving tooth 52 on the ring i6, engaging in a notch of the ring 50.Thus there is a detachable coupling between the diaphragm setting ring38 and the shutter speed setting ring i6, 58, which coupling can be setto various dierent relative positions of orientation, in accordance withdifferent exposure values to be used when taking pictures under variousdiiierent conditions of lighting, filter factor, film speed, etc. Anexposure value scale 51 is preferably marked circumferentially on thering 38, in addition to the diaphragm aperture scale, and is read inconnection with a reference point or index mark 53 on the speedadjusting ring 56, so that this scale 51 will show the relativepositions of the diaphragm aperture and shutter speed adjustments withrespect to each other, regardless of the absolute position of either oneof them. This variable coupling of the diaphragm aperture adjustment tothe shutter speed adjustment, and the use of exposure value scale inconnection therewith, are disclosed, for example, in my copending UnitedStates patent application, Serial No. 507,703, filed May 11, 1955 (nowPatent 2,887,940, granted May 26, 1959), to which reference is made forsuch further details as may be desired, although an understanding offurther details is not necessary to an understanding of the presentinvention.

When the camera is to be focused in advance of taking the picture, thediaphragm adjusting ring 36 is turned all the way in a clockwisedirection to open the diaphragm to maximum aperture, and according tothe present invention it is latched in this open position by mechanismbest shown in Figs. 2 and 3. A latchingV pin S4, extending parallel tothe optical axis, is mounted in the shutter housing for limited axialmovement and has its enlarged rear end S6 engaged in a cylindrical guideS8 in a fixed position in the shutter housing, and constantly pressedforwardly by a spring 76. The front end portion 68 of the latching pinprojects through a bore 62 in the bayonet connection ring 20 which isstationarily mounted on the front of the shutter, and through an arcuateslot (concentric with the optical axis) in the body portion 22 of theinterchangeable lens unit, the extreme front end of the latching pinengaging in a latching notch 64 formed in the edge of the diaphragmaperture adjusting ring 38 when this ring is in its positioncorresponding to maximum aperture opening of the diaphragm. When the pin54 is withdrawn rearwardly, the aperture adjusting ring 38 can be turnedcircumferentially, but if the latching pin is not otherwise restrainedit will snap forwardly (under the influence of its spring 76) into thenotch 64 Whenever the aperture adjusting ring 30 reaches its position ofmaximum aperture, thereby latching the diaphragm in fuliy open position.

Near the rear end of the pin 54, within the shutter casing, there is aforwardly faced conical shoulder 66 arranged to engage with and bepressed rearwardly by an oblique cam surface 68 of a release pawl 7i)pivotally supported in the shutter housing 12 on the pivot pin 72 (Figs..7. and 4) so as to swing in a plane perpendicular to the optical axis.The pawl 70 has a lug or arm 74 which extends rearwardly parallel to theoptical axis, out the back of the shutter casing and through the frontwall i8, to a position within the camera body, where it is suitablyconnected to the release plunger 4 of the camera in such manner thatwhen the release plunger is depressed to make the exposure, the arm orlug 74 is moved radially inwardly toward the optical axis so as to swingthe pawl 70 in a counterclockwise direction on its pivot 72. Thismovement causes the oblique cam edge 68 of the pawl to react with theconical shoulder 66 of the latching pin 54 to move the latching pinaxially rearwardly against the force of its spring 76. Also, near theend of the complete stroke of the pawl 7i?, this movement of the pawlserves to release or trigger the shutter to open and close the blades tomake an exposure, the details of the shutter mechanism itself beingunimportant for purposes of the present invention, so that it issufficient for present purposes merely to understand that the shutter isreleased or triggered near the end of the counterclockwise swingingmovement of the pawl 70.

On the front surface of a radially extending ange of the diaphragmsetting ring 38, a double armed pawl 78 is pivotally mounted at 80 andis influenced by a spring 82 tending to swing the pawl counterclockwiseon its pivot. The rear arm 84 of the pawl normally engages in aconstriction or reduced neck portion 86 near the front end of thelatching pin 54, 68, while the other arm 88 of the pawl has an obliquecam surface 98 lying just a little ahead (in a clockwise direction) ofthe abutment shoulder 4i), so that as the arm 32 of the diaphragmadjusting ring 38 swings counterclockwise under the influence of itsspring 36, it will engage the cam surface 98 and turn the pawl 78 justbefore the motion of the arm 32 is stopped by engagement with theabutment 40. This engagement of the arm 32 with the cam 90 will swingthe pawl 78 clockwise on its pivot 80, to a sucient extent to disengagethe other arm 84 o-f the pawl from the reduced neck portion 86 of thepin 54, 6i).

This embodiment of tne invention operates as follows: On the basis ofexisting illumination conditions, tilm speed, and filter factor (ifany), the operator sets the diaphragm aperture adjusting ring 38 in thedesired position of orientation relative to the shutter speed settingring 50, by moving the ring 38 forwardly against the force of its spring44, to uncouple the tooth 46 from the notch 48 and place it in any otherdesired notch 48, until the proper exposure value of the scale 5l isopposite the reference mark 53. Then the desired diaphragm aperture atwhich the photograph is to be taken is preselected by turning the ring38 to bring the desired absolute value of the diaphragm aperture on itsscale, opposite the stationary pointer 42, this adjusting motion of thediaphragm aperture preselecting ring 38 serving at the same time to turnthe shutter speed adjusting ring 50 (because of the coupling between thetwo rings) in a complementary manner, so that the exposure value is notchanged.

ln order now to be able to effect optical focusing of the camera, in thecase of a single-lens reflex camera, both the diaphragm leaves or bladesand the shutter blades must be opened. The opening of the shutter bladesfor focusing purposes is eected in a known manner the details of whichare not important for purposes of the present invention, the mechanismnot being shown in the drawings. In order to open the diaphragm leavesto maximum aperture for focusing, the diaphragm adjusting ring 30 isturned by means of the external finger piece on the arm 32, in aclockwise direction when viewed as in Fig. 3, until the front end of thelatching pin 54, 60 snaps into the recess 64 in the diaphragm ring 30,under the inuence of the spring 76.

Digital pressure on the linger piece of the arm 32 may now be released,as the latching pin S4, 68 will hold the diaphragm adjusting ring 30 inthe fully open position, as long as desired. When focusing is completedand the operator is ready to take the picture, he depresses the releaseplunger 4 on the camera body which moves the arm 74 to swing the pawl onits pivot 72. By the interaction of the oblique surfaces 68 and 66, thisdraws the latching pin 54, 60 rearwardly far enough to release thediaphragm ring 30, so that the spring 36 may begin to move the diaphragmring in a counterclockwise direction to close down the aperture of thediaphragm to the preselected value. However, the engagement of the end84 of the pawl 78 in the reduced neck 86 of the latching pin, serves toprevent the latching pin from being withdrawn all the way rearwardly atthis time, and thus prevents the pawl 70 from completing its stroke farenough to trip 0r release the shutter mechanism.

Just before the diaphragm adjusting ring 30 reaches the preselectedposition, the arm 32 engages the oblique cam end 90 of the pawl 78 andswings this pawl to release the other end 84 from the neck portion 86 ofthe latching pin 54, 60. The latching pin may now be moved furtherrearwardly, to the end of its stroke, so that the pawl 70 (previouslyblocked by the intermediate position of the latching pin) is now able tocomplete its stroke, in the latter part of which it trips or releasesthe shutter mechanism to operate the shutter to open and close theshutter blades to make the exposure.

Thus when the operator places his finger on the release plunger 4 andpresses downwardly to take the picture, there is a momentary dwell orstoppage at an intermediate point of the downward movement of therelease plunger. The movement cannot be completed, sufficiently to tripthe shutter, until the diaphragm has closed down to the preselectedaperture and it is the closing movement of the diaphragm aperture whichreleases the shutter tripping parts so that these parts may completetheir movement and trip the shutter. In this way, there is absoluteassurance that the eiective shutter actuation will not take place untilthe diaphragm has assumed the preselected aperture position.

It will also be noted that this construction is extremely simple andinexpensive, and is also designed in such a way that it does notinterfere with placing the interchangeable lens and diaphragm unit onthe camera, or taking it off the camera, regardless ofthe position inwhich the diaphragm may be set at the moment. As already mentioned, thepin 54, 60 extends through an arcuate slot in the part 22 of theinterchangeable unit, and this arcuate slot is long enough toaccommodate the pin during the necessary turning movement of theinterchangeable unit while engaging or disengaging the bayonet lugs onthe interchangeable unit and on the shutter, respectively. If theinterchangeable unit happens to be engaged with the shutter while thediaphragm is stopped down to an aperture smaller than its maximumaperture, the axial part of the engaging motion will simply cause thering 30 to engage the end of the pin 54, 60 and push the pin rearwardly,and the front end of the pin will ride on the rear face of the plate 30until the next adjusting movement of the diaphragm to maximum aperture,when the pin will snap forwardly into the notch 64.

vA slight variation of essentially the same construction is illustratedin Fig. 6, which corresponds to a fragment of Fig. 2 near the rear endof the latching pin 54, 60. In this variation, the rear end 56 of thelatching pin, instead of being received in a separate cup-shaped guide58 (as was the case in Fig. 2) simply extends rearwardly into a guidebore in the shutter mechanism plate 14 or the shutter housing 12 itself,as well seen in Fig. 6. The spring 76, as before, tends to move thelatching pin axially forwardly. The operation is exactly the same aspreviously described.

It is seen from the foregoing disclosure that the above mentionedobjects of the invention are well fullled. It is to be understood thatthe foregoing disclosure is given by way of illustrative example only,rather than by way of limitation, and that without departing from theinvention, the details may be varied within the scope of the appendedclaims.

What is claimed is:

l. A photographic camera including an objective shut ter unit having anoptical axis, an interchangeable lens unit attachable to and detachablefrom said shutter unit, interengaging means on the two units forsecuring them detachably to each other, said lens unit having anadjustable diaphragm, a diaphragm aperture adjusting member rotatablymounted on said lens unit, a spring tending to turn said adjustingmember in an aperture-reducing direction, a preselection stop memberadjustably mounted for controlling the extent to which said spring mayturn said adjusting member in an aperture-reducing direction, a latchingpin mounted in said shutter unit for limited axial movement, a latchnotch in said aperture adjusting member for receiving the end of saidlatching pin for releasably holding said adjusting member at a maximumaperture position, said latching pin having a spaced shoulder and camsurface, an exposure controlling member mounted on said shutter unit andincluding a pawl oscillatable about a rotary axis parallel to saidoptical axis and movable through a predetermined range of travel in onedirection to cause an exposure, said pawl engaging said cam surfaceduring a rst portion of its said range of travel to retract saidlatching pin from said latch notch and release said adjusting member formovement in an aperture-reducing direction, pawl means pivoted to saidlens unit for engaging said shoulder to prevent further retraction ofsaid latching pin until said -adjusting member strikes said preselectionstop member, and means for automatically pivoting said pawl means todisengage said shoulder and allow said exposure controlling member tomove through the other portion of its said range of travel to cause theexposure.

2. A construction as defined in claim 1 including a pair of arms on saidadjusting member, one of said arms being arranged to be externallyaccessible to be grasped manually to move said adjusting member to saidmaximum aperture position, said means for pivoting said pawl means beingprovided by the other of said arms.

References Cited in the le of this patent UNITED STATES PATENTS2,311,822 Frankel Feb. 23, 1943 2,319,304 Dalotel May 18, 1943 2,371,524Kals Mar. 13, 1945 2,751,828 Wirgin June 26, 1956 2,777,371 Schutz Jan.15, 1957 FOREIGN PATENTS 1,106,716 France Iuly 27, 1955

